Create a Linux VM¶

In this example we'll walk through how to create a Linux VM using Slicer on an x86_64 host, or an Arm64 host.

The /dev/kvm device must exist and be available to continue.

Create the VM configuration¶

Slicer is a long lived process that can be run in the foreground or daemonised with systemd.

To create a VM using a Linux bridge, and a disk file for storage create the following ./vm-image.yaml file:

config:
  host_groups:
  - name: vm
    storage: image
    storage_size: 25G
    count: 1
    vcpu: 2
    ram_gb: 4
    network:
      bridge: brvm0
      tap_prefix: vmtap
      gateway: 192.168.137.1/24

  github_user: alexellis

  kernel_image: "ghcr.io/openfaasltd/actuated-kernel:5.10.240-x86_64-latest"
  image: "ghcr.io/openfaasltd/slicer-systemd:5.10.240-x86_64-latest"

  hypervisor: firecracker

The storage: image setting means a disk image will be cloned from the root filesystem into a local file. It's not the fastest option for the initial setup, but it's the simplest, persistent and great for long-living VMs.

Now, open a new terminal window, or ideally launch tmux so you can leave the binary running in the background.

sudo -E slicer up ./vm-image.yaml

Having customised the github_user to your own username, your SSH keys will have been fetched from your profile, and preinstalled into the VM.

On your workstation, add any routes that are specified so you can access the VMs on their own network.

Connect with:

ssh ubuntu@192.168.137.2

View the serial console¶

The logs from the serial console including the output from the boot process are available on disk:

$ sudo tail -f /var/log/slicer/vm-1.txt

         Starting OpenBSD Secure Shell server...
[  OK  ] Started OpenBSD Secure Shell server.
[  OK  ] Reached target Multi-User System.
[  OK  ] Reached target Graphical Interface.
         Starting Record Runlevel Change in UTMP...
[  OK  ] Finished Record Runlevel Change in UTMP.

Ubuntu 22.04.5 LTS vm-1 ttyS0

vm-1 login:

If you want to tail the logs from all available VMs at once, use fstail via arkade get fstail:

sudo -E fstail /var/log/slicer/

Configuration for an Arm VM¶

The only changes needed to the vm.yaml file are to the kernel_image and image fields:

-  kernel_image: "ghcr.io/openfaasltd/actuated-kernel:5.10.240-x86_64-latest"
-  image: "ghcr.io/openfaasltd/slicer-systemd:5.10.240-x86_64-latest"
+  kernel_image: "ghcr.io/openfaasltd/actuated-kernel:6.1.90-aarch64-latest"
+  image: "ghcr.io/openfaasltd/slicer-systemd-arm64:6.1.90-aarch64-latest"

Launch a second VM¶

Edit the count field, and set it to 2.

Then hit Control + C and launch slicer again.

You'll see the second VM come online and can connect to it over SSH.

Enable the HTTP API¶

The API is used by the slicer vm commands, and can also be used directly via curl.

  api:
    port: 8080
    bind_address: "127.0.0.1:"
    auth:
      enabled: true

The auth token will be created at /var/lib/slicer/token and can be used via a Authorization: Bearer header.

i.e.

curl -s http://127.0.0.1:8080/nodes/ -H "Authorization: Bearer $(sudo cat /var/lib/slicer/token)" | jq

Enable the Serial Over SSH Console¶

The Serial Over SSH (SOS) console can be used to log into a VM without a password, and without any form of networking enabled.

  ssh:
    port: 2222
    bind_address: "0.0.0.0:"

Example:

ssh -p 2222 ubuntu@localhost